Field of the Invention
The present invention relates to a flow-channel device using a light-emission detecting method.
Description of the Related Art
A μ-TAS (Micro Total Analysis system) means a device or the like which uses a fine reaction field therein that is produced by the application of a lithography process and a thick film process technology, and is used for detecting as small an amount as a sample of nanoliter scale or subjecting the same to the reaction. In recent years, the μ-TAS is used in chemical analysis, reagent preparation, chemical synthesis, reaction detection and the like. A representative μ-TAS includes, for instance, a DNA chip, a Lab on a Chip, a microarray and a protein chip. The μ-TAS is used for medical inspection/diagnosis, and is applied to: a region of a genetic test, a chromosomal test, a cytoscopy and the like; a biotechnology; a test of a trace amount of a substance in an environment; an investigation on a farming environment of an agricultural product and the like; a genetic test for an agricultural product; and the like.
In a conventional inspection method, a process and an operation of equipment to be used are complicated, and a skillful operation is needed. Accordingly, these inspections have been mainly conducted while relying on the manipulation of a laboratory technician. However, when the μ-TAS is used, automation is enabled, and anyone can easily conduct the inspection. In addition, the μ-TAS also brings about various effects such as an increase of the speed, an increase of the accuracy, a reduction of the cost, a reduction of the period of time needed, and a reduction of the environmental impact.
In the μ-TAS, a flow channel and a detection of emitted light such as the measurement of fluorescence are occasionally used in combination. On this occasion, the amount of an object to be inspected is so trace that it is occasionally necessary to reduce the light which is emitted from another substance than a liquid to be inspected and causes a noise.
Methods for suppressing the light emission which causes the noise in a device using a flow channel are disclosed in Japanese Patent Application Laid-Open No. 2006-078414 and Japanese Patent Application Laid-Open No. 2002-286627. In Japanese Patent Application Laid-Open No. 2006-078414, a light-shielding portion is provided on the surface of a substrate along the flow channel, and the light-shielding portion shields the fluorescence which is emitted from the substrate. In Japanese Patent Application Laid-Open No. 2002-286627, a flow-channel device is disclosed which is formed by using an adhesive and has a light-shielding layer therein.
In the invention disclosed in Japanese Patent Application Laid-Open No. 2006-078414, a flow channel is produced by a joining method such as hot press which does not use an adhesive. In order to practice such a joining method, such conditions are needed that surfaces of substrates or the like to be joined are completely flat or can be sufficiently deformed by an action from the outside when being joined (that substrate is resin, or the like), as is shown in the cross-sectional view which is illustrated in FIG. 1B in Japanese Patent Application Laid-Open No. 2006-078414.
Specifically, when a brittle material such as quartz is used, after the light-shielding portion has been formed, the surface to be joined needs to be flattened. In order to flatten the surface to be joined, a method is considered which includes film-forming the light-shielding portion, then forming another material so as to become thicker than the light-shielding portion, and then polishing the surface; or a method is considered which includes firstly removing a part of the plate substrate corresponding to the thickness of the light-shielding portion by some process, forming a light-shielding film, and then polishing the surface to remove an unnecessary portion and flatten the surface. However, any method is complicated and has been disadvantageous also in the point of the cost.
Japanese Patent Application Laid-Open No. 2002-286627 discloses a flow-channel device having a light-shielding layer therein. However, in this application, a procedure of producing a flow-channel device is not disclosed. In addition, a pattern of the light-shielding film layer is not formed in consideration of an assembling operation necessary when the flow-channel device is used.